Plants are typically at their most vulnerable when they are just beginning to emerge from the soil. Gardeners located in cold climates may construct miniature greenhouses or “cold frames” in which plants may be germinated. A typical cold frame comprises a rectangular box covered with a removable glass or plastic cover, and is permanently installed in a garden. Once the plants are sufficiently robust to withstand the elements, the gardener transplants them from the cold frame to an open air garden plot.